Electrics and gas
An oil line is buried under a patio and was not traced. Which leak path is untested?
The buried oil line under the patio is the untested leak path. The pipe was not traced, so joints, corrosion and any weep into the ground or the patio base were not seen and were not pressure-tested. A home survey does not test an oil line by looking at slabs. Staining, a smell or a dead patch of plants would be clues only, and none of those was turned into a test here. The report notes that the line is buried and untraced. It has not decided that the line is tight, or that it is leaking.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Oil feed pipe runs from a tank to a boiler, often in the ground, where a pinhole can wet soil for a long time before anything shows indoors. A patio built over that run hides the pipe, the joints and any protection around it. The surveyor could not lift the patio as part of this visit and did not claim a route under it. The boiler end and the tank end, if they were visible, do not prove the buried middle. That middle is the path still untested.
Ask the solicitor whether any plan shows the oil line, and whether an installer left a pressure-test note, and keep those papers out of the survey wording. An oil technician can trace and test the line if you instruct them. Tell a lender the buried section was not inspected and no tightness test was done. Do not describe the patio as evidence that the pipe is sound because the slabs looked dry.
What should you ask your surveyor?
- Was the oil line under the patio traced or pressure-tested?
- Do the visible tank and boiler ends stand in for the buried middle?
- Is any installer plan being kept separate from this report?
What are the typical next steps?
- Treat the buried oil line as an untested leak path.
- Ask the solicitor for any plan or pressure-test note.
- Do not describe dry slabs as a tightness test.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Does the survey include a test of the boiler's combustion?
No. This question is about the buried oil line, and the visit did not trace or pressure-test that pipe. Combustion, flue gases and burner settings were not tested either, unless a separate specialist note says so, and this report does not. Keep any later oil-fired service distinct from the survey. The untested leak path remains the line under the patio.
Can a stain on a slab be written up as a proved leak?
A stain is a clue, not a proved leak, and this visit did not test the line. The report's point is that the buried run was not traced, so neither tightness nor a leak has been shown. Do not upgrade a mark on concrete into a failed pipe. A technician's test would be new work with its own result.